Stair construction

ABSTRACT

A plurality of thin plywood tread and riser members are joined perpendicular to each other to form prefabricated tread and riser units for a stair construction. The tread and riser units are constructed to be supported on spaced stringers which extend between a lower level and an upper level. Each riser member is received in a downwardly opening groove formed in a toe cleat on each adjacent tread member and each riser member can have equal portions removed therefrom to compensate for different distances between the upper and lower levels. Fasteners are provided to secure each of the tread and riser units to the stringers and the fasteners are associated with a downwardly facing surface of a heel cleat on each tread member to secure respective tread and riser units to the stringers in a manner to compensate for varying angular relationships of the stringers to the horizontal which occurs as a result of the different distances between the upper and lower levels.

United States Patent 91 [111 3,909,997 Eickhof Get. 7, 1975 [5 STAIR CONSTRUCTION [76] Inventor: John K. Eickhoi, Box 599, 'F Purser Crookston Minn 56716 Assistant Exammerl-lenry Raduazo [22] Filed: Jan. 9, 1974 [52] US. Cl 52/188; 52/191 [51] Int. Cl. E04F 11/02; E04F 11/10 [58] Field of Search 52/182, 183, 184, 185, 52/186,191,179, 753 Y, 188

[56] References Cited UNITED STATES PATENTS 2,321,120 6/1943 Baker... 52/753 Y 2,760,239 8/1956 Riley 52/183 3,564,793 2/1971 Willfurth.. 52/182 3,608,256 9/1971 .lefferys 5 2/188 FOREIGN PATENTS OR APPLICATIONS 599,115 3/1948 United Kingdom 52/182 147,366 1/1931 Switzerland 52/179 589,888 7/1947 United Kingdom 52/182 1,438 5/1887 Sweden 52/182 6,106 1/1906 France 52/182 1,284,651 1/1962 France 52/188 [5 7] ABSTRACT A plurality of thin plywood tread and riser members are joined perpendicular to each other to form prefabricated tread and riser units for a stair construction. The tread and riser units are constructed to be supported on spaced stringers which extend between a lower level and an upper level. Each riser member is received in a downwardly opening groove formed in a toe cleat on each adjacent tread member and each riser member can have equal portions removed therefrom to compensate for different distances between the upper and lower levels. Fasteners are provided to secure each of the tread and riser units to the stringers and the fasteners are associated with a downwardly facing surface of a heel cleat on each tread member to secure respective tread and riser units to the stringers in a manner to compensate for varying angular relationships of the stringers to the horizontal which occurs as a result of the different distances between the upper and lower levels.

10 Claims, 8 Drawing Figures US, Patsnt 0a. 7,1975 Sheet 1 of 2 3,909,997

US. Patent Oct. 7,1975 Sheet 2 of2 3,909,997

i ii /17239.

STAIR' CONSTRUCTION BACKGROUND OFTTHE INVENTION 1. Field of the Invention The present invention relates generally to stair construction and is directed more particularly to prefabricated types of stair construction.

positioned within the notches and are generally constructed from relatively thick lumber to meet safety standards of construction. On many occasions the vertical distance between the upper and lower levels differs. This of course means that the stringers of the stairway must be disposed at a different angular relationship to the horizontal and consequently considerable calculation must take place to insure that all of the risers of the stair construction are of generally equal vertical'dimensions and that the notches. are correctly positioned inthe stringers. Quite often thesecalculations are inaccurate, resulting in a bottom stair riser having a vertical dimension which is substantially less than that of the remaining stair risers. Further, this type of stair construction requires that all of the notches formed inthe stringers must be accurately cut so that the tread and riser members will be properly aligned and engaged with each other. Very often this is not accomplished and results in a weakened stair construction which may sag and squeak as load forces are applied thereto. Also, the time required to construct these conventional type stairs and the need for relatively thick lumber components have resulted in undersirably high construction expenses.

Various stair constructions have been proposed for eliminating the problems involved in notching the stringer members as well as for compensating for differ ent vertical distances between upper and lower levels. However, these proposed stair constructions have only partially solved the problems of the conventional stair construction and on occasion have presented additional problems in that some components thereof are not aesthetically appealing, do not lend themselves to quick and easy assembly, and other components thereof are still formed from relatively thick and heavy material.

SUMMARY OF THE INVENTION A tread member and a riser member, both made of plywood, are joined along one longitudinal edge of each by a heel cleat to. form a prefabricated tread and riser unit for a stair construction. The other longitudinaledge of each tread member is provided with a toe cleat having a downwardly opening longitudinally extending groove formed therein, sized to receive the other, upwardly extending longitudinal edge of a riser of an adjacent tread and riser unit. A plurality of prefabricated tread and riser units are assembled by mounting the units between stringers, which stringers are supported to extend between an upper and a lower level. Opposite transverse edges of the tread members and risermembers overlie the stringers with the upper longitudinal edge of each riser positioned inthe downwardly opening grooves'of an adjacent tread and riser unit. Fastening devices secure each tread and riser unit to the stringers. The upper edges of all of the riser members can have equal portions removed therefrom to compensate for different distances between the upper and lower levels so that all of the riser members in the stair construction have equal vertical dimensions between the treads. The fasteners, which are associated with downwardly facing surfaces of the heel cleats, are constructed to compensate for the different angular relationship of the stringers relative to the horizontal which occurs as a result of differing distances between the upper and lower levels.

Also, a pair of side wall members are affixed to opposite transverse edges and outer stringer surfaces to encompass and connect the opposite sides of the stair structure. This allows carpeting or other stair covering material to be easily applied to the tread and riser units without interference from mounting bracket members, other projections or the like heretofore utilized to effect stair construction, or from gaps or the like between various components of the stair construction.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view in side elevation of a stair construction extending between an upper and a lower level and constructed in accordance with the present invention, a portion being removed for clarity of illustration;

FIG. 2 is a view in vertical section as seen generally from the line 2-2 of FIG. 1, showing the stair construction in rear elevation, portions thereof being bro ken away and shown in section;

FIG. 3 is a fragmentary view in perspective showing a portion of the structure of FIG. 1 as seen generally from the rear and one side;

FIG. 4 is a view in perspective from the rear and bottom of a tread and riser unit utilizing the stair construction of the present invention;

FIG. 5 is a view in vertical section on an enlarged scale as seen generally from the line 5-5 of FIG. 2;

FIG. 6 is a view similar to FIG. 1 of a modified embodiment of the present invention;

FIG. 7 is a view similar to FIG. 3 illustrating the modified embodiment of FIG. 6; and

FIG. 8 is an enlarged vertical section similar to FIG. 5 illustrating the modified embodiment of FIGS. 6 and 7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring initially to FIGS. 1-5 of the drawings a stair construction extending between a lower level A and an upper level B is indicated generally by the numeral 10. A pair of spaced stringers 11 are affixed to and extend from a transverse plate member 12 upwardly to a transverse header of a dwelling structure adjacent the upper level B. A pair of straps 13 are affixed to the upper ends of the stringers 11 and to the transverse header of the dwelling structure to support the upper ends of the stringers 11. While a plate 12 and straps 13 are shown for supporting the stringers 11, it will be appreciated that other supporting means may be utilized to support the stringers 1 1 in their positions of FIG. 1 or other similar positions. A plurality of tread members 14 and riser members 15 are provided which extend between the longitudinal stringers 11. Each. tread member 14 and riser member 15 has opposite longitudinal edges 16a, 16b and 17a, 17b respectively, and transverse edges 18, 19 respectively. Each one of the tread members 14 is connected along longitudinal edge 16a with one of the riser members 15 to form a prefabricated tread and riser unit shown specifically in FIG. 4 and indicated generally by the letter C. The riser member 15 in each unit C includes a lower portion adjacent the longitudinal edge 17a which extends beyond the longitudinal edge 16a of a respective tread member 14.

A separate heel cleat 22 extends along the longitudinal edges 16a, 17a of the tread and riser 14, 15 respectively, between the transverse edges 18, 19 thereof and is secured to the lower portion of the riser member 15 and to the adjacent undersurface of the tread member 14. As shown particularly in FIG. 5, heel cleat 22 is affixed to the tread member 14 and riser member 15 by means of a suitable adhesive 23 and a plurality of fasteners such as nails 24. The particular connection heretofore described, for joining the tread 14 to the riser 15, provides an extremely strong joint structure for reasons which will hereinafter become apparent.

A separate toe cleat 25 is affixed to and extends along the other longitudinal edge 16b of each tread member 14 between opposite transverse edges 18 thereof, In a manner similar to heel cleat 22, toe cleat 25 is secured to the corresponding undersurface of the tread member 14 by means of a suitable adhesive 23 and a plurality of fasteners such as nails 24. Each of the heel cleats and toe cleats 22, 25 respectively is affixed to respective tread members 14 so as to define downwardly facing cleat surfaces 22a, 25a respectively.

Note that for vertical forces members 15, 22 and 25 form an I-beam of which riser 15 is the web and cleats 22 and 25 are the lower and upper flanges respectively.

A rear support means for engaging the stringers 11 includes a pair of L-shaped brackets 26. Each L-shaped bracket has leg portions 27, 28. Leg portion 27 of each of the brackets 26 is shown as underlying and being fastened to the downwardly facing surface 22a of the heel cleat 22 by means of a fastener such as a nail 24. The other leg portion 28 of each of the L-shaped brackets 26 is secured to an inner vertically disposed surface of one of the stringers 11 by means of fasteners such as nails 24. As can be seen particularly in FIGS. 4 and 5, the leg portions 27 of the L-shaped brackets 26 are each positioned to also underlie the longitudinal edge 17a of the riser 15. This provides additional support to the stair structure 10 since supporting forces are applied to both the riser l and toe cleat 22 as well as the tread member 14 supported on the toe cleat 22.

A front support means for the tread and riser units C is provided by forming a downwardly opening longitudinally extending groove 29 in the downwardly facing surface 25a of respective toe cleats 25 in each of the tread and riser units C. The grooves 29 are sized to receive the other longitudinal edge 17b of a riser member 15 of an adjacent one of the tread and riser units C. Thus, when the tread and riser units are mounted to the stringers 11, in the manner illustrated in FIGS. 1-3 and 5 of the drawings, each groove 29 is positioned to receive the longitudinal edge 17b of a next lower tread and riser unit C. This provides a desired degree of vertical support to the outermost longitudinal edges 16b of the tread members 14 as well as a desired degree of lateral support to the riser members 15. As shown in FIGS. l-3 stair construction includes a final riser member 30 having opposite longitudinal edges 31a, 3 lb. One edge 31a is secured to the adjacent surface of the transverse plate 12 and the other edge 31b is received in the longitudinal groove 29 of the lowermost one of the toe cleats 25. This method of joining and supporting the plurality of tread and riser units C in the stair construction 10 allows for a great latitude of different distances between the lower level A and the upper level B without significant modification of the stair construction 10. For example, if the vertical distance, indicated at D in FIG. 1, between the lower level A and the upper level B were 1 inch less, an installer would merely have to reduce the included angle, indicated at E in FIG. 1, of the stringer 11 relative to the horizontal and thereafter move a A inch portion of each of the riser members 15 and 30 along respective longitudinal edges 17b, 31b thereof. This is an extremely simple procedure as compared to that which would be necessary in the construction of a conventional stairway.

Preferably, tread members 14 and riser members 15 are formed from plywood sheet material having a thickness dimension of approximately three-eighths of an inch. This, of course, departs from normal stair construction wherein the tread members generally include a thickness dimension in the neighborhood of 1% inches and the riser members A of an inch. This normal thickness of material not only weighs more, but also results in the use of a comparatively greater amount of lumber. This has been felt to be necessary because of the particular construction now generally used and because certain building code restrictions must be met with this construction. The particular construction of the present invention, however, provides a stair structure 10 which is assembled in such a manner as to allow the use of the relatively thin plywood tread and riser members 14, 15 respectively, while at the same time meeting building code restrictions set forth for stair construction. However, it will be appreciated that if conditions of use dictate, the above stair construction can readily utilize thicker, stronger materials to satisfy such conditions.

In the vein of using less material in the construction of stairs, which not only reduces the cost thereof but alleviates the problem of shortages, stringers 11 have been formed from 2 by 4 lengths of material instead of the more conventional 2 by 12 stringers now required to meet building codes. However, under conditions of greater load stress or where stair positions are such that intermediate supporting walls or members are not present, additional lengths of 2 by 4 supports may be used as stringers or vertical supports or supports and stringers of larger dimension (2 by 6, etc.) may be used.

In the stair construction 10 shown, the tread and riser units C are positioned on the stringers 11 such that opposite transverse edges 18, 19 of the tread and riser members 14, 15 respectively and the outer surfaces of the stringers 11 are positioned in two parallel planes, see FIG. 2. This permits a pair of side wall members 32, 33 to be affixed to opposite transverse edges of the tread members 14 and riser members 15 and to outer surfaces of the stringer members 11 to encompass and connect the opposite sides of the stair structure 10. These side wall members 32, 33 are formed from a relatively thin material such as 4 inch pine. The side wall members 32, 33 add some additional strength to the stairway, and finish off opposite transverse edges of the tread and riser units C so that no cracks or gaps appear at their juncture with theside wall members 32, 33 to spoil the aesthetic appearance of the stair construction.

Further, they protect adjacent walls from being scuffed and marred from foot traffic. The lack of gaps or the like, as well as the lack of unnecessary projections caused by mounting brackets, etc., provides a stair construction which can be finished off with a suitable covering, material (such as rubber mats or carpeting, not shown) to improve the appearance of the stairway with a minimum of time, effort and expense.

MODIFIED EMBODIMENT Referring to FIGS. 68, a slightly modified stairconstruction is illustrated and indicated generally by the numeral 10'. Stair construction 10 is generally similar to that shown in FIGS. 1-5 and like parts thereof will carry like reference numerals with a prime mark added. Stair constructionltl is more particularly adaptable to use in situations where the vertical dimension D between the lower level A and the upper level B is a standard or known distance or wherein a stair construction is required in which this distance is not critical. As an example of the latter, portable stair systems for building contractors at construction sites can provide a sturdy access to upper levels of a dwelling construction. Usually upper ends of these stair systems need by positioned only closely adjacent an upper level. In this respect, each of the tread and riser units C is constructed with a tread member 14 and a riser member 15' joined along their respective longitudinaledges 16a and 1711 by a heel cleat 22'; The heel cleat 22 extends along the edges 16a, 17a" in a manner similar to the tread'and riser units C. The rear support means for the tread and riser unit C differs in that the heel cleat 22 of each unit C has a downwardly facing surface 22a which is generally coplanar with other surfaces 22a of other heel cleats 22. All of the surfaces 22a lie in a plane which corresponds to the plane of adjacent upper surfaces of the stringers 11', when the stringers are positioned at an appropriate angle to support the tread and riser units C for a given or known distance D between the lower and upper levels A, B. The support means for the structures of FIGS. 6-8 includes a plurality of fasteners, such as the relatively long nails 34 illustrated in FIG. 8. The nails 34 are driven through each of the tread members 14, respective heel cleats 22, and into each of the stringers 11.

Like stair construction 10, stair construction 10 in cludes a final riser member 30. Riser member 30 has one edge 31a secured to an adjacent portion of the transverse base plate 12 and the other end thereof 31b received in the longitudinal groove 29 of the lowermost one of the toe cleats 25'. Stair construction 10' may include side wall members (not shown) similar to the wall members 32, 33 of stair construction 10.

In each case, a stair construction 10, 10 has been disclosed in which a minimum amount of materials are required and which is adaptable to substantially all conditions of use. Also, a stair construction is disclosed which requires a minimum of skill to adapt it to the various conditions of use, which is relatively inexpensive and which meets all the requirements as to weight or load restrictions contained within present building codes. Further, while I have shown fastening devices such as nails 24 for additionally securing the glued joints together, present glues afford sufficient strength in and of themselves to sustain the joints under all but the most difficult design conditions. Under conditions normally encountered, nails are not needed to secure the-plywood to the cleatsbecause the adhesives are sufficiently' strong.

--What is claimed is: r

1. As an article of manufacture, a prefabricated stair building unit comprising: i

a wooden tread member having front and rear edges and a lower surface, a wooden riser memberhaving top and bottom edges and a front surface; I a wooden heel cleat extending.longitudinally of the tread surface having upper and lower surfaces and a rear surface perpendicular to said upper surface; a wooden toe cleat extending longitudinally of the tread surface having upper and lower surfaces; means rigidly securing the rear surface of said heel cleat to the front surface of said riser member along the bottom edge thereof to form a beam of which the riser'member is the web and the heel cleat is the lower flange; means rigidly securing the lower surface of said tread member to the upper surface of said heelcleat with the rear edge of said tread member abutting the front surface of said riser member; means rigidly securing the upper surface of said toe cleatto the lower surface: of'said tread member along the front'edge thereof; and groove means in the lower surface of said toe cleat for receiving the upper edge of another riser member, so that said toe cleat may form therewith the upper flange of said beam. 2.'Thestructure of claim 1 whereinsaid tread and riser members are made of plywood.

3."The structure'of claim 1 wherein the top edge of said riser is free for trimming to accord with the desired riser height of a stair as determined by the total height between levels to be connected by the stairs and the intended number of steps.

4. A stairway comprising, in combination: a pair of notchless stringers having upper, inner, and

outer surfaces; a stair building unit comprising;

a wooden tread member having front and rear edges and a lower surface;

a wooden riser member having top and bottom edges and a front surface;

a wooden heel cleat extending longitudinally of the tread surface having upper and lower surfaces and a rear surface perpendicular to said upper surface;

a wooden toe cleat extending longitudinally of the tread surface having upper and lower surfaces;

means rigidly securing the rear surface of said heel cleat to the front surface of said riser member along the bottom edge thereof to form a beam of which the riser member is the web and the heel cleat is the lower flange;

means rigidly securing the lower surface of said tread member to the upper surface of said heel cleat with the rear edge of said tread member abutting the front surface of said riser member;

means rigidly securing the upper surface of said toe cleat to the lower surface of said tread member along the front edge thereof;

and groove means in the lower surface of said toe cleat for receiving the upper edge of another riser member, so that said toe cleat may form therewith the upper flange of said beam;

rear support means including said stringers for engaging the heel cleat of said unit from below and forpreventing the relative movement between said stringers and said heel cleat;

and front support means engaging the groove in the toe cleat of said unit from below.

5. The structure of claim 4 in which said front support means includes the top edge of the riser of another of said stair building units.

6. The structure of claim 4 in which said front support means includes a final riser member.

7. A stairway comprising, in combination:

a pairof notchless stringers having upper, inner, and

outer surfaces;

a plurality of stair building units, each comprising:

a wooden tread member having front and rear edges and a lower surface;

a wooden riser member having top and bottom edges and a front surface;

a wooden heel cleat extending longitudinally of the tread surface having upper and lower surfaces and a rear surface perpendicular to said upper surface;

a wooden toe cleat extending longitudinally of the tread surface having upper and lower surfaces;

means rigidly securing the rear surface of said heel cleat to the front surface of said riser member along the bottom edge thereof to form a beam of which the riser member is the web and the heel cleat is the lower flange;

means rigidly securing the lower surface of said tread member to the upper surface of said heel cleat with the rear edge of said tread member abutting the front surface of said riser member;

means rigidly securing the upper surface of said toe cleat to the lower surface of said tread member along the front edge thereof;

and groove means in the lower surface of said toe cleat for receiving the upper edge of another riser member, so that said toe cleat may form therewith the upper flange of said beam;

means rigidly securing the top edge of the riser member of one of said units in supporting relation in the groove in the toe cleat in another of said units, so that said toe cleat forms the upper flange of said beam;

and means including said stringers for separately supporting from below the ends of the heel cleats of said units and for securing said heel cleats to said stringers.

8. The structure of claim 7 in which the last-named means comprises brackets, secured to the inner faces of said stringers, upon which said heel cleats are secured.

9. The structure of claim 8 in which each bracket engages both the lower surface of the heel cleat and the bottom edge of the riser secured thereto, at one end thereof.

10. The structure of claim 7 in which the lower surfaces of said heel cleats are generally coplanar, and the upper surfaces of said stringers are generally coplanar in the same plane, and in which the last-named means comprises fasteners extending from said heel cleats into said stringer. 

1. As an article of manufacture, a prefabricated stair building unit comprising: a wooden tread member having front and rear edges and a lower surface; a wooden riser member having top and bottom edges and a front surface; a wooden heel cleat extending longitudinally of the tread surface having upper and lower surfaces and a rear surface perpendicular to said upper surface; a wooden toe cleat extending longitudinally of the tread surface having uPper and lower surfaces; means rigidly securing the rear surface of said heel cleat to the front surface of said riser member along the bottom edge thereof to form a beam of which the riser member is the web and the heel cleat is the lower flange; means rigidly securing the lower surface of said tread member to the upper surface of said heel cleat with the rear edge of said tread member abutting the front surface of said riser member; means rigidly securing the upper surface of said toe cleat to the lower surface of said tread member along the front edge thereof; and groove means in the lower surface of said toe cleat for receiving the upper edge of another riser member, so that said toe cleat may form therewith the upper flange of said beam.
 2. The structure of claim 1 wherein said tread and riser members are made of plywood.
 3. The structure of claim 1 wherein the top edge of said riser is free for trimming to accord with the desired riser height of a stair as determined by the total height between levels to be connected by the stairs and the intended number of steps.
 4. A stairway comprising, in combination: a pair of notchless stringers having upper, inner, and outer surfaces; a stair building unit comprising; a wooden tread member having front and rear edges and a lower surface; a wooden riser member having top and bottom edges and a front surface; a wooden heel cleat extending longitudinally of the tread surface having upper and lower surfaces and a rear surface perpendicular to said upper surface; a wooden toe cleat extending longitudinally of the tread surface having upper and lower surfaces; means rigidly securing the rear surface of said heel cleat to the front surface of said riser member along the bottom edge thereof to form a beam of which the riser member is the web and the heel cleat is the lower flange; means rigidly securing the lower surface of said tread member to the upper surface of said heel cleat with the rear edge of said tread member abutting the front surface of said riser member; means rigidly securing the upper surface of said toe cleat to the lower surface of said tread member along the front edge thereof; and groove means in the lower surface of said toe cleat for receiving the upper edge of another riser member, so that said toe cleat may form therewith the upper flange of said beam; rear support means including said stringers for engaging the heel cleat of said unit from below and for preventing the relative movement between said stringers and said heel cleat; and front support means engaging the groove in the toe cleat of said unit from below.
 5. The structure of claim 4 in which said front support means includes the top edge of the riser of another of said stair building units.
 6. The structure of claim 4 in which said front support means includes a final riser member.
 7. A stairway comprising, in combination: a pair of notchless stringers having upper, inner, and outer surfaces; a plurality of stair building units, each comprising: a wooden tread member having front and rear edges and a lower surface; a wooden riser member having top and bottom edges and a front surface; a wooden heel cleat extending longitudinally of the tread surface having upper and lower surfaces and a rear surface perpendicular to said upper surface; a wooden toe cleat extending longitudinally of the tread surface having upper and lower surfaces; means rigidly securing the rear surface of said heel cleat to the front surface of said riser member along the bottom edge thereof to form a beam of which the riser member is the web and the heel cleat is the lower flange; means rigidly securing the lower surface of said tread member to the upper surface of said heel cleat with the rear edge of said tread member abutting the front surface of said riser member; means rigidly securing the upper surface of said toe cleat to the loweR surface of said tread member along the front edge thereof; and groove means in the lower surface of said toe cleat for receiving the upper edge of another riser member, so that said toe cleat may form therewith the upper flange of said beam; means rigidly securing the top edge of the riser member of one of said units in supporting relation in the groove in the toe cleat in another of said units, so that said toe cleat forms the upper flange of said beam; and means including said stringers for separately supporting from below the ends of the heel cleats of said units and for securing said heel cleats to said stringers.
 8. The structure of claim 7 in which the last-named means comprises brackets, secured to the inner faces of said stringers, upon which said heel cleats are secured.
 9. The structure of claim 8 in which each bracket engages both the lower surface of the heel cleat and the bottom edge of the riser secured thereto, at one end thereof.
 10. The structure of claim 7 in which the lower surfaces of said heel cleats are generally coplanar, and the upper surfaces of said stringers are generally coplanar in the same plane, and in which the last-named means comprises fasteners extending from said heel cleats into said stringer. 